This invention relates to a method of making a metal slab with a non-uniform cross-sectional shape and an associated integrally stiffened metal structure using spray casting.
Metal products for use as fuselages for aircrafts, reinforced skins for space vehicles, integrally stiffened sheet for trains or transportation vehicles and heat exchangers can have a flat portion with ribs extending from the flat portion. These metal products can be made by attaching the upstanding ribs to a flat rolled product by a variety of joining methods such as riveting, fastening, bonding or welding. However, a disadvantage of this process is that joining places are sources of failure. A further disadvantage is that this process requires a separate joining operation and the need for inspection.
There are known methods of making an integrally stiffened structure. One known method involves extrusion. Another known method involves machining a metal piece to form the integrally stiffened structure. Both of these methods have inherent disadvantages, the most prominent of which is the high cost of producing the integrally stiffened structure.
Thus, there remains a need for making a metal slab with a non-uniform cross-sectional shape which can then be worked, such as by shaped hot rolling, into an integrally stiffened metal structure. The method should produce a metal structure having excellent structural characteristics while at the same time reducing the costs and inefficiencies associated with known prior art methods.